Bio 120 MT 2

Midterm 2 bio 120 Egan USC

Prokaryotes

The first single celled organism

Proto- cells

First cell like containers with a pre- lipid bilayer

Stromatolites

Layered rocks that form when prokaryotes bind thin films of sediment together

What time did fossilized stromatolites exist

3.5 billion years ago, Prokaryotes were sole inhabitants for 1.5 billion years

oxygenic photosynthesis

photosynthesis that produces oxygen only pyhla present is Cyanobacteria

The Great Oxidation Event

the seas and lakes became saturated with O2, O2 began to "gas out" and enter the atmosphere and accumulate 2.4 billion years ago.

Anaerobic respiration

bacterial that metabolize and live in absence of O2

Anaerobic habitats

An area with no oxygen where many prokaryotes ran to hide in the great oxidation event

cellular respiration

the process by which cells use oxygen to produce energy from food

Eukaryotes

Developed after the oxidation event unlike prokaryotes, they have nucleus, membrane bound organelles

Endsymbiosis

Eukaryotes came from this ancestor. Formed by a prokaryotic cell engulfed a small cell and evolve into a mitochondrion

T/F all eukaryotic cells have mitochondria but not all have plastids (chloroplasts and related organelles)

True

Serial endosymbiosis

hypothesis that mitochondria evolved before plastids through a sequence of endosymbiotic events

Support for Endosymbiosis

Homologous to those found in bacterial membranes, can trace and translate their own DNA, and ribosomes are similar to those bacteria in size, RNA sequence, and antibiotic sensitivity

Cambrian Explosion

An explosion of animal diversity right after the very first development of multi-cellar organism (all life is still mostly in ocean)

When did plants move to land?

First was fungi about 3.2 billion years ago as they advance into seeded plants on earth from photosynthesis fungi in ocean

Mycorrhizae Mutualism

Mutualism between plants and mycorrhizal fungi are seen in oldest fossilized plants

Arthropods (lobsters) and Tetrapod (bone hand fish)

First animals to colonize land.

Diferences in speciation and extinction rates

plate tectonics, mass extinction, and adaptive radiation

Pangaea

the supercontinent about 250 million years ago altered many habitats: ocean basins became deeper, most shallow water habitant was destroyed, and the interior of the continent became drier than coaster regions

continental drift

movement in the mantle cause the plates to gradually shift in a process

allopatric speciation

Species diverge into geological isolated types happens in large scale due to continental drift

mass extinctions list 5

Ordovician Silurian extinction, permian triassic extinction, late Devonian extinction, triassic Jurassic extinction, cretaceous Paleocene extinction, and holocene extinction

Adaptive radiation

a rapid period of evolution change where many new species arise and adapt to different ecological territories

silversword alliance

Hawaiian ancestor plant that created many species of plants on Hawaii

Species can analogous to individuals

speciation is their birth, extinction is their death, and new species that arise are their offspring

Evolutionary change in gene regulation

morphological changes caused by mutations affecting developmental gene regulation

homeotic genes

master regulatory genes that determine where an organism features will appear

How can phenotypes evolve out?

Change of way it is expressed or can be mutation of that gene

Homeobox genes

a 60 amino acid encoding DNA sequence has been identified throughout the three kingdom of organisms

How genes

a class of of homoetnoic genes provide positional information in animal embryos

Heterochrony

an evolutionary change in the rate or timing of developmental events

Paedomorphosis

development of reproduction organs accelerates relative to other organs

Hardy Weinberg Equilibrium Requirements

1) No Mutation 2) No Migration/gene Flow 3)Large Population size 4) Random 5) No natural Selection

Deviations from Hardy Weinberg

Gene Flow, Genetic drift, and Natural Selection

Bottle Neck

Type of Genetic Drift, There is a drastic reduction in population size due to a sudden change in evironment

Genetic Drift

Chance event fluctuation in frequencies, lowers genetic variation, can make genes fixed very big deal in small populations examples: Bottle neck and Founder Effect

Gene Flow

Movement of Alleles throughout populations via fertile individuals or gametes, can reduce variation from population to population because they become similar

Natural Selection

Adapt to fit the environment in order to survived, has three rules

Types of Altering gene number

Subfuncitonalization, gene dosage, neofunctionalization

Three rules for natural selection

have to be hereditable has to have different fitness

Observations of life

unity, differences, adapt to biotic and abiotic

Directional Selection

Type of natural selection where individuals with traits that are at one extreme of the range are favored, leading to a shift in the population’s average phenotype over time.

Disruptive Selection

Type of natural selection where extreme phenotypes have a higher fitness than average phenotypes, causing a spilt in a population towards two distinct traits

Stabilizing Selection

Natural Selection that favors intermediate phenotypes, reducing genetic variation and maintaining the average trait value in a population

Relative Fitness

Best fitness that is availability not always the best! remember frog slides

Adaptive evolution

Natural selection works and evolves species to be fit for evironment

Sexual selection

choose mate, cause sexual dimorphism (sexes look different)

intrasexual selection

same sex fight for other sex

intersexual selection

one sex chooses the other

Balancing Sections

When you are utilizing two phenotypes ex-frequency dependent and heterozygote advantage

Frequency Dependent

Phenotype based on common type, example: sex question in that quiz ☹

Heterozygous advantage

when fitness of heterozygous is higher than both homozygotes Example: sickle cell anemia

Micro Evolution

Change in allele frequency of a population over time

Macro evolution

pattern change at a species level

intraspecific variation

microevolution with genes and alleles

interspecific variation

macroevolution looking at species (similar and different to evolution)

Biological species concept

Says species is a group that makes viable fertile offspring and don't produce viable/ fertile offspring with other species: through has the limitation of when you can’t see mating (fossils, asexual, prokaryotes) Absence of gene flow occur between morphically and ecological distinct species

Why do certain species stay together in biological species concept

Gene flow

reproductive isolation

prevent hybrids, because two species can’t reproduce

prezygotic barriers

prevent making a zygote via no interactions of the species, genetics not lining up, or even gametes not being compatible

habitat isolation

When different species live in different habitats and rarely come into contact prezygotic

Temporal isolation

A type of reproductive isolation where two species reproduce at different times, preventing them from mating pre zygotic

Behavioral Isolation

A reproductive barrier of the same species have different courtship rituals or behaviors, preventing successful mating. pre zygotic (bird dancing! 🙂 )

mechanical isolation

Reproductive barrier caused by physical differences preventing mating or successful fertilization between species. general’s don’t work pre-zygotic (snail genitals)

gametic isolation

Reproduction barrier preventing interbreeding between species due to differences in their gametes such as incompatible sperm, and eggs. prezygotic (sea urchin)

Reduced hybrid viability

A phenomenon where offspring produce from the mating of two different species have reduced chances of serval success

hybrid breakdown

First gen is fertile but offspring in next generation are sterile

morphological species concept

Distinguish species by structural features and is used fossils and asexual species. Limitation: subjective to user’s eyes

Allopatric speciation

geographically isolated example: isthmus of Panama

genetic isolation can occur as a result of

gene pools isolating and diverging because of mutation, selection or genetic drift

Sympatric Speciation

Not geographically isolated Example: polyploidy, sexual selection, natural selection as a result of habitat differentiation (freshwater v salt fish in same area) and food source change

Autoploidy

>2 sets chromosomes from same species

Allopolyploids

>2 sets of chromosomes from different species

gene flow

allopathic and sympatric speciation occurs as result of interruption of

Allopatric Speciation Summary

Geographically isolation restricts gene flow between populations Intrinsics barriers to reproduction arise due to genetic change drive by processes including divergent selection and genetic drift reproductive barriers prevent interbreeding even if contact is restored between populations

Sympatric speciation

A reproductive barrier isolates subset of a population without geographic separation from parent species Sympatric speciation can result from polyploidy, Sexual selection, or natural selection resulting from a switch in food source or habitat

Charles Darwin noticed that flinches on different islands of the Galápagos Islands were similar but that their beaks differed What explanation for these differences did he propose?

A. The beaks of the finches are adapted to way the bird usually gets food.

B. The beaks of the flinches are randomly selected by genetic mutation

C. The different beaks would one day evolve into identical beaks

D. Beak size is related to the size of the flinch

Which of the following is not a rule of evolution?

A. natural selection can only increase or decrease heritable traits that are variable in a population

B. Individuals evolve over time

C. Favorable traits vary with the environment

D. Population evolve over time

3. Select all that apply for “descent with

modification.”

a. All organisms are related by descent from a common ancestor that lived in the past

b. Was created by Carl Linnaeus

c. “Descent” involves shared ancestry,

resulting in shared characteristics

d. “Modification” involves the

accumulation of evolution

A,C,D B is wrong it’s Charles Darwin

4 a. Similarity due to shared ancestry between a pair

of structures or genes in different taxa (Ex: Development of limb bones in different species)

Homologous Structure

4b. First name in Binomial nomenclature

genus

4c. Second name in binomial nomenclature

specific epithet

4d. Diagrams that reflect hypotheses that reflect hypotheses about the relationships among groups

evolutionary tree

4e. An evolutionary process in which humans consciousness select for or against particular features in organism

artificial selection

Scientific Name

Used to classify species because common names are useless for conveying evolutionary similarities

Taxonomy

the process of identifying classifying, and naming species

Carolus Linnaenous

botanist developer of taxonomy

Taxon

the named taxonomic unit at any level of hierarchy

specific epithet

second name of species

Why is taxonomy classifying important?

It helps us describe features in organisms such as if it’s cells or eukaryote or bacteria or archaea

Phylogenetic trees

Systematist depict evolutionary relationships in branching (evolutionary tree), has a tree root = common ancestor of this group animal

Out group in phylogenetic tree

the species group kicked out to side in a phylogenetic tree, this species shares a trait with other species so diverged early on

Sister taxa

only two to share a node in phylogenetic tree

Polytomy

when we are not too sure where the 3 or more species diverged but we know they have common ancestor so we connect them with node in phylogenic tree

monophyletic group

group that includes 1 common ancestor and an out group

Paraphyletic group

group doesn’t include all descents of a common ancestor

Polyphyletic group

common ancestor not shared but tax are group based on common traits but district related species

Inferring phylogenies

multiple data types are used to determine phylogenetic relationships. Morphologies(historically), Genes (More recently), Genomes (most recently)

Homologous structures

structures in different animals that arise from shared ancestry derived from common ancestor